A transparent diode with high rectifying ratio using amorphous indium-gallium-zinc oxide/SiNx coupled junction

Abstract

We introduce a transparent diode that shows both high rectifying ratio and low leakage current at process temperature below 250 degrees C. This device is clearly distinguished from all previous transparent diodes in that the rectifying behavior results from the junction between a semiconductor (amorphous indium-gallium-zinc oxide (a-IGZO)) and insulator (SiNx). We systematically study the properties of each junction within the device structure and demonstrate that the a-IGZO/SiNx junction is the source of the outstanding rectification. The electrical characteristics of this transparent diode are: 2.8A/cm(2) on-current density measured at -7V; lower than 7.3 x 10(-9) A/cm(2) off-current density; 2.53 ideality factor; and high rectifying ratio of 10(8)-10(9). Furthermore, the diode structure has a transmittance of over 80% across the visible light range. The operating principle of the indium-tin oxide (ITO)/a-IGZO/SiNx/ITO device was examined with an aid of the energy band diagram and we propose a preliminary model for the rectifying behavior. Finally, we suggest further directions for research on this transparent diode. (C) 2015 AIP Publishing LLC.